:3U2 COALFIELDS AND COLLIERIES OF AUSTRALIA. 



The air compressor is a single stage compressor, made by 



Oliver and Co., of Chesterfield, England; the steam and air 



-cylinders, both of which are water-jacketed, are placed 



parallel with each other. Spring valves are used for the air 



inlet valves. 



For ventilation, they have one of Waddle's patent fans 

 and engine. The fan is trumpet-mouthed, and is 28ft. ex- 

 treme diameter. The engine cylinder is 22in. in diameter. 



Water is pumped from 230ft. down, where there is a 

 lodgment: from the bottom of this shaft, the water is bailed. 

 An Evans' pump is being installed. They have to use safety 

 lamps underground. 



One of the most interesting features about this colliery is 

 the fact that the original steel head frame, when erected, w y as 

 found to be too short, as the coal could not be raised suffi- 

 ciently high for screening and subsequent operations, so the 

 whole structure was raised bodily 14ft., and the additional 

 length added to the bottom. First of all, the back stays were 

 disconnected, also the cross-stays at the top, which connected 

 them, to the main structure, and they were supported in posi- 

 tion by a cross-beam placed under the back stays, and a long 

 post in the middle. Bearers were placed on either side of the 

 four main legs, thus connecting them in pairs; and these 

 bearers were well bolted together. Other beams were placed 

 under the bearers, and at right angles to them. Hydraulic 

 jacks were then placed below, and the whole structure raised 

 evenly. thiy ropes were used to steady the head frame as it 

 was being raised. As the structure was lifted from the 

 ground, pig-sty timbering was placed beneath to support it. 

 The angle iron of the original and added lengths were butted 

 together, and bolted to fish-plates, 2ft. 9in. long, placed on 

 the outside. On account of the splay of the legs, the concrete 

 base to which the legs were fastened by eight bolts, had to 

 be built further out than those used for the original shorter 

 head frame. The back stays were then lifted up, and con- 

 nected with the main structure, the extra length added to the 

 bottom of them, and fastened to concrete piers by six bolts. 

 The back stay supports were then connected up. The bottom 

 part of the built-up steel legs was filled with concrete raised 

 slightly in the centre, so as to prevent water lodging there. 



The pit-head pulleys were made strong enough for the 

 work required of them. The plurnmer blocks have large 

 bearing surfaces, the spindles of the pullies being large so as 

 to reduce the pressure per square inch of surface. Brasses 

 are on the lower half of the plummer block only, where all 

 the wear is, there being no occasion to have any lining on the 

 top. The spindle is lubricated automatically by means of a 

 loose steel ring, which encircles it, and is caused to revolve 



